The candidate obtained a full mark in all of the 15 questions attempted in the test. Since the test carries equal marks for all questions, the candidate earned 60% marks in the test.

To find the total number of questions in the test, we can set up a proportion. We know that the candidate attempted 15 questions out of the total number of questions in the test. We also know that the candidate achieved 60% of the total marks available in the test.

Let`s set up the proportion:

15 (questions attempted) / x (total number of questions) = 60% (60/100)

To solve this proportion, we need to find the value of x.

To do this, we can cross-multiply and solve for x:

15 * 100 = x * 60

1500 = 60x

Dividing both sides of the equation by 60, we find:

x = 25

Therefore, the total number of questions in the test is 25.

Alert - correct answer should be 25.